Biomechanical analysis of wrapping of the moderately dilated ascending aorta

Moderately dilated ascending aorta-The right wrap?

External reinforcement of the dilated or thin-walled aorta has been tried for nearly half a century. A range of materials has been used as external support. This commentary assesses the evidence that exists regarding the efficacy of wrapping the aorta as well as compares the different options available with a particular focus on the usage of the autologous pericardium.

Systolic stretching of the ascending aorta

INTRODUCTION

Longitudinal stretching of the aorta due to systolic heart motion contributes to the stress in the wall of the ascending aorta. The objective of this study was to assess longitudinal systolic stretching of the aorta and its correlation with the diameters of the ascending aorta and the aortic root.

MATERIAL AND METHODS

Aortographies of 122 patients were analyzed. The longitudinal systolic stretching of the aorta caused by the contraction of the heart during systole and the maximum dimensions of the aortic root and ascending aorta were measured in all patients.

RESULTS

The maximum dimension of the aortic root was on average 34.9 ±4.5 mm and the mean diameter of the ascending aorta was 33.9 ±5.4 mm. The systolic aortic stretching negatively correlated with age (r = -0.49, p < 0.001) and the diameter of the tubular ascending aorta (r = -0.44, p < 0.001). There was no significant correlation between the stretching and the dimension of the aortic root (r = -0.11, p = 0.239). There was a statistically significant (p < 0.001) difference in the longitudinal aortic stretching values between patients with a normal aortic valve (10.6 ±3.1 mm) and an aortic valve pathology (8.0 ±3.2 mm in all patients with an aortic valve pathology; 7.5 ±4.3 mm in isolated aortic stenosis, 8.5 ±2.9 mm in the case of isolated insufficiency, 8.2 ±2.8 mm for valves that were both stenotic and insufficient).

CONCLUSIONS

Systolic aortic stretching negatively correlates with the diameter of the tubular ascending aorta and the age of the patients, and does not correlate with the diameter of the aortic root. It is lower in patients with an aortic valve pathology.

Endovascular Hybrid Repair of True Ascending Aortic Aneurysms Using Double Graft Wrapping to Prepare a Landing Zone for Ascending Aortic Stent-Graft Placement: A Cohort Study

Purpose: To describe a hybrid procedure that avoids cardiopulmonary bypass to treat patients with true ascending aortic aneurysms without a suitable proximal landing zone for endovascular repair. Material and Methods: Thirteen consecutive patients (mean age 75.9±6.5 years; 8 women) with true ascending aortic aneurysms were treated with the endovascular hybrid repair of true aortic aneurysms (EHTA) approach, which consists of a conventional sternotomy with double wrapping of the ascending aorta followed by staged stent-graft placement. Via sternotomy, a polypropylene mesh trimmed to downsize the aneurysm is placed around the dilated ascending aorta and sutured to the adventitia. A similarly trimmed polytetrafluoroethylene graft is placed loosely around the first wrap to avoid adhesions and secure the proximal landing zone. There is no need for cardiopulmonary bypass. A few days later, a standard thoracic stent-graft is deployed via either a transaxillary or transfemoral access; chimney or bypass grafts are used as needed to revascularize the supra-aortic vessels. Results: The ascending aortic diameter was reduced from a mean 5.7 cm (range 4.8-6.5) to 3.9 cm (range 3.2-4.3) after wrapping. The mean interval between surgery and stent-graft placement was 5 days. In this interval, 2 patients with significant reduction in the diameter of the ascending aorta elected to forego placement of a stent-graft. Of the 11 patients who underwent the full hybrid EHTA procedure, the ascending aortic stent-graft was combined with a chimney graft in the innominate artery in 4 cases. In 1 patient, a supra-aortic debranching procedure using a bifurcated Dacron graft to the innominate and left common carotid arteries was performed after wrapping with the polypropylene mesh. There was no mortality or neurological complication. A sternal wound infection required a prolonged hospital stay. At a mean follow-up of 13.8 months (range 3-24), there has been no death, type I endoleak, or sign of aneurysm enlargement on imaging. Conclusion: This technique permits complete endovascular exclusion of an ascending aortic aneurysm in a less invasive approach than standard open repair. Although this is only a small cohort of patients without long-term follow-up, it seems that this hybrid procedure is associated with low morbidity and mortality. It offers a beating-heart approach to treat true ascending aortic aneurysms in selected high-risk patients.

Efficacy of ascending aortic banding technique concomitant with type I hybrid aortic arch repair in high-risk patients

Banding of the ascending aorta has been introduced as a less complex procedure to optimize the proximal landing zone of the stent graft in hybrid aortic arch surgery. However, data about the long-term results and effects of this technique are still limited. We aimed to study the efficacy of banding of the ascending aorta in hybrid aortic arch repair. The study included 11 high-risk patients with dilated ascending aorta (wider than 38 mm in diameter) undergoing ascending aortic banding for hybrid arch repair. Clinical outcomes, including technical success, endoleaks, perioperative mortality and morbidity, and sequential remodeling of the ascending aorta were investigated. The average diameter of the ascending aorta had been reduced (p = 0.02) from 42.1 mm (range = 39.0-46.4) to 37.2 mm (range = 35.6-38.6) after banding procedure. The technical success rate was 100.0%. No type I endoleak occurred, but 2 cases of distal stent graft-induced new entry required re-interventions. The 5-year survival and freedom from aortic events rates both were 81.8%. The ascending aortic diameter remained stable and no proximal migration of the stent graft was observed during the study period. The 5-year results validated the durability of this therapeutic modality, especially in high-risk patients.

Off-Pump Plicating Ascending Aortoplasty With External Wrapping: Magnum in Parvo

BACKGROUND

Isolated, fusiform aneurysms, exclusively affecting the tubular portion of the ascending aorta, are rare. Surgical treatment aims to change their natural course, reducing individual and cumulative risks of rupture, dissection and death. Open tubular graft replacement still remains the procedure of choice, despite significant risks. In permanent pursuit for optimal, alternative surgical strategy in high-risk patients, less invasive and off-pump plicating ascending aortoplasty with modified external Dacron graft wrapping seems to be a reliable choice.

METHODS

Two (2) consecutive patients were operated on. The same preoperative calculations and slightly different operative techniques were applied regarding surgical exposure and wrapping graft orientation. Immediate and late follow-up (5 years) results were compared.

RESULTS

Absolute and indexed target ascending aortic diameters remained acceptable (<2.1cm/m² considered the upper normal range for adults). There were no significant changes in proximal and distal aortic diameters. Ascending aortic silhouette on contrast enhanced multi-detector CT was better with Dacron wrapping graft tailored to have its grooves in the longitudinal direction. Upper mini-sternotomy was quite appropriate for this procedure, from a surgical point of view, and was safe for the patient.

CONCLUSIONS

Careful patient selection and using the current model of preoperative calculations and surgical technique resulted in acceptable and stable ascending aortoplasty in high-risk patients 5 years after surgery.

Surgical treatment with wrapping of the moderately-dilated ascending aorta

Background

The aim of this study is to present early and mid results associated with the treatment of dilatation of the ascending aorta using the wrapping technique.

Methods

A total of 54 patients (16 males, 38 females; mean age 56.9±12.7 years; range 21 to 77 years) who were subjected to the wrapping technique due to dilatation of the ascending aorta between January 2010 and Fabruary 2017 were retrospectively analyzed. The Dacron grafts were used in all patients. Wrapping was performed in all patients in combination with the other cardiac surgical procedures. Wrapping was performed with aortoplasty in 32 patients and as an isolated procedure in 22 patients. Preoperative clinical findings, concomitant cardiac procedures, intraoperative parameters, postoperative early and long-term outcomes were evaluated. The ascending aorta and descending aorta diameters, ejection fraction, left ventricle end-diastolic and end-systolic diameters were measured using a computed tomography scan and/or transthoracic echocardiography after surgery, and was compared with the preoperative values.

Results

The median follow-up was 3.8 (range, 1 to 7) years. No intraoperative complication associated with the wrapping procedure was reported in any of the patients. One patient died during the early postoperative period. Relapse-free intra-arterial fibrinolysis was used to correct postoperative cerebral infarct in one patient without any sequelae. Revision surgery was required in two patients due to bleeding and in another two patients due to sternal dehiscence. A postoperative decrease in the aortic diameter and an increase in the ejection fraction were found to be statistically significant. Findings such as sinus of Valsalva and distal aortic dilation, rupture, pseudoaneurysm, and graft mobilization were not observed during follow-up.

Conclusion

Our study results show that the wrapping techniques may be safely performed in patients with moderate dilatation of the aorta who do not require replacement of the ascending aorta.

Wrapping of the ascending aorta revisited-is there any role left for conservative treatment of ascending aortic aneurysm?

Dilatation of the ascending aorta (AA) is a common finding in patients with aortic valve disease. The clinical practice guidelines recommend replacing the AA whenever the diameter exceeds 45 mm. However, no consensus has been reached regarding the approach when the aorta is only moderately dilated. Although the risk in aorta replacement is generally low, it may be higher when associated with other complex surgical procedures or it is carried out in elderly patients or patients with significant comorbidity. This would justify the use of alternative surgical techniques, which reduce surgical risk and guarantee a durable correction of the aortic pathology. Conservative treatment of aneurysms of the AA via wrapping with different synthetic materials has been implemented for many years. The most commonly used technical variant is wrapping the dilated aorta with a vascular prosthesis with a predetermined diameter. When this technique is adequately applied, it immediately reduces the diameter of the AA and, to a lesser degree, the diameter of the aortic root and arch, while at the same time it reinforces the weak aortic wall. These effects lead to a drop-in wall shear stress and in the risk of aortic dissection and rupture, and persist over time. Although the low elasticity of the external support causes significant changes in the histologic structure of the aortic wall, mainly atrophy and alterations typical of a foreign body-induced reaction, this does not seem to involve a higher risk of complications. In some selected patients, this technique may be used in cases other than post-stenotic aortopathy, and also in aortas with a larger diameter.

A 'compare and contrast' exercise: wrapping versus personalised external aortic root support (PEARS)

Wrapping of the aorta and personalised external aortic root support (PEARS) both have the purpose of preventing further expansion of the ascending aorta in order to reduce the risk of aortic dissection and to spare the patient the disastrous consequences of aortic rupture. For the first time, Plonek and colleagues have reported systematically the CT appearances of a series of cases of wrapping. They illustrate the important finding that there are residual spaces between the aorta and the wrap. PEARS by contrast is intimately in contact with the aorta due to its personalised design and is fully incorporated due it construction from a porous mesh. A limitation of PEARS is that it is, of its nature, a planned and elective operation while wrapping can be undertaken during an emergency operation and can be used without prior planning as an intraoperative decision.

Computed tomography angiography of aorta subjected to external wrapping

BACKGROUND

External wrapping is a surgical technique used in patients with dilated ascending aorta. To date, there is no available data describing the radiographic features of the aorta subjected to external wrapping using a straight corrugated Dacron vascular prosthesis. The aim of this study was to find distinctive radiographic features of an externally constricted aorta.

METHODS

Preoperative and early postoperative (7th postoperative day) CT angiography images of ten patients who underwent wrapping procedures were assessed and compared. The images were analyzed in order to find characteristic features of CT angiography images of the ascending aorta subjected to external wrapping.

RESULTS

The CT-angiography images showed that the aortic wall deformed significantly (the wall plicated) after the wrapping procedure in one patient, whose aortic diameter was decreased by 47 %. The remaining nine patients did not have significant aortic wall deformations. All patients presented with a periaortic mass. This was a collection of blood clots and pericardial fluid that filled the empty space in the pericardium following a decrease in the diameter of the ascending aorta. A very thin (<1 mm) crescent-shaped uncontrasted layer was noticed between the aorta and the periaortic area in all patients. This, in turn, was an empty space between the aorta and the corrugated vascular prosthesis.

CONCLUSIONS

The CT-angiography images of the aorta subjected to external wrapping may have unique features that are not observed after other operations on the ascending aorta. The knowledge about the details of this surgical procedure helps to correctly assess these images.

Treatment of isolated ascending aortic aneurysm by off-pump epiaortic wrapping is safe and durable

OBJECTIVES

Isolated ascending aortic aneurysm (iAA) is usually treated by open graft repair requiring sternotomy, cardiopulmonary bypass (CPB) and cardioplegia. This approach carries significant mortality in older patients or those presenting with comorbidities. We report an original series of patients presenting with iAA and treated with epiaortic wrapping by using a synthetic mesh. This less invasive aortic repair technique allows reducing the aortic diameter to a predefined value and is performed without CPB.

METHODS

Data from patients presenting with an iAA and treated with the wrapping technique (WT) by polypropylene/polyester mesh from November 2006 to July 2015 were collected. The end-points that were analysed included maximal aortic transverse diameter, perioperative mortality and morbidity, survival, freedom from reinterventions and aortic valve function during follow-up. The maximal aneurysm transverse diameter was analysed based on contrast-enhanced computed tomography (CTA) or magnetic resonance (MR) performed preoperatively, and during the follow-up.

RESULTS

The off-pump WT was used in 33 cases with no perioperative mortality. The median radiological follow-up was 33.47 (range: 1-106) months. Overall, the WT achieved a 30% diameter reduction. The mean preoperative and postoperative ascending aortic transverse diameter was 5.5 cm [standard deviation (SD): 0.6] and 3.7 cm (SD: 0.30), respectively (P = 0.001). In addition, CTA or MR follow-up showed stable diameters at the level of the aortic root and the distal ascending aorta. No death occurred during the follow-up. At 5 years, the estimated freedom rate from reinterventions of the aortic root and ascending aorta was 94%.

CONCLUSIONS

This series shows that the WT with a polypropylene/polyester mesh allows safe off-pump treatment of patients with iAA. Mid- and long-term results are promising. This technique could be an attractive alternative, especially for patients unfit for aortic surgery with CPB and cardioplegia.

Single center experience with wrapping of the dilated ascending aorta

Background

External wrapping is a surgical technique performed in patients with a dilated ascending aorta. The aim of this study is to present the mid-term results of wrapping of the dilated ascending aorta.

Methods

34 patients (mean age: 64.4 ± 10.8 years, 21 males) with a dilated ascending aorta were operated on at a single cardiac surgery center using a wrapping technique. The aortas were wrapped with 32–36 mm straight Dacron vascular prostheses. The aortic wall was not excised in any of the patients. Wrapping was performed concomitant to other cardiac surgery procedures in 30 patients (88 %), which involved surgery on the aortic valve in 28 patients (82 %).

Results

The mean follow-up time was 19.5 ± 8.3 months (median: 18 months, range: 12–36 months). None of the patients died or had aortic complications during the hospital stay and the follow-up period. A rethoracotomy had to be performed due to excessive postoperative bleeding in two patients. One patient was diagnosed with a transient ischemic attack on the 4th postoperative day, while another had respiratory failure requiring prolonged intubation. No redilatation of the ascending aorta or dislocation of the wrap was noticed in any of the patients.

Conclusions

According to our study, external wrapping of the ascending aorta has good short-term results and may be regarded as a safe surgical option for patients with a moderately dilated ascending aorta.